Hectares to Acres Converter

1 hectare equals about 2.47105 acres, or roughly 2.5 acres as a quick mental factor. The exact derivation: 1 hectare is exactly 10,000 sq m, and 1 acre is exactly 4,046.8564224 sq m (43,560 international sq ft x 0.09290304 sq m per sq ft). Dividing gives 10,000 / 4,046.8564224 = 2.47105381467 acres per hectare. Going the other way, 1 acre is about 0.40469 hectares. For ballpark estimates, multiply hectares by 2.5 to get acres, or by 0.4 to go from acres back to hectares; both are within 1.2 percent of exact.

Because the hectare was designed that way. It is one square hectometer (1 hm x 1 hm), where a hectometer is 100 m. So a hectare is exactly a square 100 m on each side, 100 m x 100 m = 10,000 sq m. The name comes from the SI prefix hecto (100) plus are, an older metric unit equal to 100 sq m (a 10 m by 10 m square). 1 hectare = 100 ares = 10,000 sq m = 0.01 sq km. The hectare is not strictly an SI unit but is accepted for use with the SI by the International Bureau of Weights and Measures (BIPM) specifically because it dominates land-area work.

Almost everywhere outside the United States. EU farms report area in hectares under the Common Agricultural Policy. Eurostat, FAO, and UN environmental reports use hectares for deforestation, protected-area, and agricultural-yield statistics. Australia, New Zealand, Canada, Latin America, and most of Asia use hectares for land registry, forestry, and farming. The US is the major holdout, sticking to acres for real estate, farm subsidies, and zoning. Even in the US, scientific work, federal environmental reporting (EPA, NASA, USDA satellite surveys), and any cross-border land-use study tend to be in hectares because the international datasets are in hectares.

Inheritance from medieval English surveying, and inertia. The acre was standardized in 13th-century England as 1 furlong by 1 chain (660 ft x 66 ft = 43,560 sq ft), where the chain came from Edmund Gunter's 22-yard surveying chain and the furlong came from the practical length of a plowed furrow. US public land was surveyed in the 1800s on this system (the Public Land Survey System divides land into 640-acre sections, 1 mile on each side), so every deed, plat, and zoning map in the country uses acres. Switching would require rewriting millions of land records, mortgage forms, and tax assessments. The US officially adopted the metric system in 1975 (Metric Conversion Act), but with no compulsion, so legacy land units stayed.

A hectare is a square 100 m on each side. For larger references, Vatican City covers about 49 hectares, Central Park about 341 hectares, and Manhattan about 5,860 hectares. The total area of the United States is about 983 million hectares, while the contiguous states cover less than that.